io.github.whippetdb.db.api

Interface Db

All Known Implementing Classes:

DbProxy, HybridDb

public interface Db

Raw interface to a database. Defines CRUD operations on key-value pairs and lifecycle commands.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	Db.PutHandler<T> Interface to receive a result of put() operation and optionally convert it to an object.
static interface	Db.ScanHandler Interface to receive a result of scan() operation.
static interface	Db.SeekHandler<T> Interface to receive a result of seek() operation and optionally convert it to an object.
static class	Db.Type

Method Summary

Modifier and Type	Method and Description
long	allocatedSize() Total allocated memory for this db, file or RAM.
default void	clear()
void	close() Close the backing file.
void	commit() Mark the end of transaction.
default void	delete(MemIO key, long keyOff, int keyLen)
void	discard() Discard changes after last commit
void	flush() Immediately persist the commited transations.
java.lang.Integer	keySize() Key size, non-null indicates that this db has fixed-size keys.
default java.lang.Integer	maxKeySize() Max key size, if known.
default java.lang.Integer	maxValueSize() Max value size, if known.
default void	put(MemArray key, java.util.function.BiConsumer<java.lang.Boolean,MemDataArray> consumer)
default <T> T	put(MemArray key, Db.PutHandler<T> consumer)
<T> T	put(MemIO key, long keyOff, int keyLen, Db.PutHandler<T> handler) Insert or visit a value for a key.
void	scan(Db.ScanHandler handler)
default void	seek(MemArray key, java.util.function.Consumer<MemDataArray> consumer)
default <T> T	seek(MemArray key, Db.SeekHandler<T> consumer)
<T> T	seek(MemIO key, long keyOff, int keyLen, Db.SeekHandler<T> handler) Visit a value for a key.
java.lang.Integer	valueSize() Value size, non-null indicates that this db has fixed-size values.

Method Detail

keySize

java.lang.Integer keySize()

Key size, non-null indicates that this db has fixed-size keys. If present, keyLen parameter in seek()/put()/delete() is ignored.

maxKeySize

default java.lang.Integer maxKeySize()

Max key size, if known. If present, keyLen parameter in seek()/put()/delete() is checked against it.

valueSize

java.lang.Integer valueSize()

Value size, non-null indicates that this db has fixed-size values.

maxValueSize

default java.lang.Integer maxValueSize()

Max value size, if known. If present, operations on value in seek()/put() are checked against it.

seek

<T> T seek(MemIO key,
           long keyOff,
           int keyLen,
           Db.SeekHandler<T> handler)

Visit a value for a key. If the key doesn't exist, a handler will receive null arguments. A handler is allowed to change the value on the fly. If the db has fixed-size keys: - keyLen is ignored (the db will use the size it knows). If the db has fixed-size values: - reading/writing is checked against this size, - initially value is filled by zeros, all changes are persistent. If the db has variable-size keys: - keyLen is respected, - if maxKeySize is present, keyLen is checked against it. If the db has variable-size values: - value may be cast to MemDataBuffer and resized - reading/writing follow the rules for MemDataBuffer - if maxValueSize is present, reading/writing/resizing is checked against it

Parameters:

key - - key memory

keyOff - - key start

keyLen - - key length

handler - - value handler

put

<T> T put(MemIO key,
          long keyOff,
          int keyLen,
          Db.PutHandler<T> handler)

Insert or visit a value for a key. The boolean parameter of a handler indicates whether the key was just inserted. The value is always non-null. A handler is allowed to change the value on the fly. If the db has fixed-size keys: - keyLen is ignored (the db will use the size it knows). If the db has fixed-size values: - reading/writing is checked against this size, - initially value is filled by zeros, all changes are persistent. If the db has variable-size keys: - keyLen is respected, - if maxKeySize is present, keyLen is checked against it. If the db has variable-size values: - value may be cast to MemDataBuffer and resized, - reading/writing follow the rules for MemDataBuffer, - initially value is empty (zero-size), all changes are persistent, - if maxValueSize is present, reading/writing/resizing is checked against it.

Parameters:

key - - key memory

keyOff - - actual key start

keyLen - - actual key length

consumer - - visitor

scan

void scan(Db.ScanHandler handler)

commit

void commit()

Mark the end of transaction. In general, the transaction is NOT immediately persisted. The immediate durability may be enabled by DbBuilder flags.

discard

void discard()

Discard changes after last commit

flush

void flush()

Immediately persist the commited transations.

close

void close()

Close the backing file. If journaling is enabled, persist all transactions to the main file and delete the transaction log.

allocatedSize

long allocatedSize()

Total allocated memory for this db, file or RAM.

seek

default <T> T seek(MemArray key,
                   Db.SeekHandler<T> consumer)

seek

default void seek(MemArray key,
                  java.util.function.Consumer<MemDataArray> consumer)

put

default <T> T put(MemArray key,
                  Db.PutHandler<T> consumer)

put

default void put(MemArray key,
                 java.util.function.BiConsumer<java.lang.Boolean,MemDataArray> consumer)

delete

default void delete(MemIO key,
                    long keyOff,
                    int keyLen)

clear

default void clear()